KR100550497B1 - Manufacturing method for surge absorber - Google Patents

Abstract

The present invention uses a metal thin film as a discharge electrode to improve the response speed to the abnormal voltage while absorbing the abnormal voltage in a short time, while forming a protective film on the metal thin film to prevent the metal thin film from being damaged by the discharge energy surge absorber Extends the service life of the repeater.

In addition, the present invention simplifies the manufacturing process of the surge absorber according to the protective film arrangement while the protective film is properly disposed on the metal thin film to effectively prevent damage to the metal thin film.

Description

Manufacturing method for surge absorber

1 is a cross-sectional view of a conventional surge absorber.

2 is a flowchart illustrating a process of manufacturing a surge absorber according to an embodiment of the present invention.

3 is a cross-sectional view illustrating a metal thin film deposited on a non-conductive member.

4 is a cross-sectional view illustrating a conductive ceramic thin film formed as a protective film on a metal thin film.

5 is a cross-sectional view illustrating a state in which a discharge gap is formed in the metal thin film by laser cutting the metal thin film and the conductive ceramic thin film.

FIG. 6 is a cross-sectional view illustrating a state in which the surge absorber of FIG. 5 is mounted in a receiving tube to complete a surge absorber.

7 is a flowchart illustrating a process of manufacturing a surge absorber according to another embodiment of the present invention.

8 is a cross-sectional view illustrating a metal thin film deposited on a non-conductive member.

9 is a cross-sectional view illustrating the formation of an intermediate film on a metal thin film.

10 is a cross-sectional view showing the deposition of a metal thin film to form a protective film on the intermediate film.

FIG. 11 is a cross-sectional view illustrating chemically changing a metal thin film deposited in FIG. 10 into a conductive ceramic thin film.

12 is a cross-sectional view of a metal thin film, an intermediate film, and a conductive ceramic thin film formed by laser cutting to form a discharge gap in the metal thin film.

FIG. 13 is a cross-sectional view illustrating a state in which the surge absorber of FIG. 12 is mounted in a receiving tube to complete a surge absorber.

* Description of the code for the main functions of the drawings

10 non-conductive member 11 metal thin film

11a: conductive ceramic thin film 12: discharge gap

20: receiving tube 20a: inert gas

21: sealing electrode 22: terminal electrode

23: lead wire

The present invention relates to a surge absorber, and more particularly, to a method for manufacturing a surge absorber in which a surge absorbing element is enclosed in a tube maintaining insulation while an inert gas is filled therein.

Surge absorber is mainly installed in the connection part with communication line of communication electronic device such as telephone, fax, modem or CRT driving circuit, and the part which is easy to receive electric shock by abnormal voltage such as lightning surge or static electricity. By discharging the discharge energy by gas discharge, it is a device to prevent the printed circuit board on which the electronic device is mounted due to the abnormal voltage.

A conventional surge absorber accommodates a surge absorbing element 3 in a glass tube 1 filled with an inert gas, as shown in FIG. Both ends of the glass tube 1 are provided with a sealing electrode 2 for sealing the glass tube 1, and the sealing electrode 2 is electrically connected to the terminal electrodes 4 provided at both ends of the surge absorption element 3. do.

The surge absorption element 3 includes a cylindrical non-conductive member 3a, and a conductive film 3b divided by a discharge gap is formed on the surface of the non-conductive member 3a so as to act as a discharge electrode. It is deposited to surround the member 3a.

Conventionally, a metal thin film such as titanium (Ti) or nickel (Ni), which has relatively high electrical conductivity, is used as the conductive film 3b for forming a discharge electrode in order to improve the response speed due to an abnormal voltage.

However, although the metal thin film is excellent in response speed, since the surge resistance and heat resistance are relatively low, when the abnormal voltage is introduced and gas discharge occurs, the metal thin film may be damaged by the discharge energy generated during gas discharge. That is, due to the discharge energy generated during gas discharge, the metal thin film may be deformed due to electric shock due to electric migration, or the metal thin film may be melted due to vaporization due to instantaneous temperature rise, resulting in repeated lifespan. There is a problem of shortening.

To this end, instead of the metal thin film, a conductive electrode thin film having a higher bonding strength and melting point than the metal thin film has excellent resistance to surge and heat resistance is formed as a discharge electrode. For example, titanium (Ti), a metal bonding material used as a metal thin film, has a melting point of 1668 ° C., while titanium nitride (TiN), a covalent bonding material used as a conductive ceramic thin film, has a melting point of 3290 ° C. on titanium. Compared to titanium (Ti), the surge resistance and heat resistance characteristics are relatively better than that of titanium (Ti).

However, the conductive ceramic thin film has a problem that the surge absorber cannot absorb the abnormal voltage in a short time by increasing the series resistance of the surge absorber because the electrical resistance is about 100 times higher than that of the metal thin film. .

The present invention is to solve the above problems, an object of the present invention by using a metal thin film as a discharge electrode to improve the response speed to the abnormal voltage while absorbing the abnormal voltage in a short time, while forming a protective film on the metal thin film The present invention provides a method of manufacturing a surge absorber that can prolong the service life of a surge absorber by preventing the metal thin film from being damaged by discharge energy.

In addition, another object of the present invention is to provide a method for manufacturing a surge absorber that can simplify the manufacturing process of the surge absorber according to the protective film arrangement by effectively disposing the protective film on the metal thin film to effectively prevent damage to the metal thin film.

The manufacturing method of the surge absorber of the present invention for achieving the above object is accommodated in a receiving tube filled with an inert gas therein, and having a nonconductive member and a discharge electrode divided by a discharge gap and provided in the nonconductive member. A method of manufacturing a surge absorber having a surge absorber, the method comprising: depositing a metal thin film on the nonconductive member, and preventing the discharge energy generated during gas discharge due to an abnormal voltage to be transmitted to the metal thin film. A protective gap is formed, and a discharge gap is formed to divide the metal thin film so that the metal thin film can act as a discharge electrode.

In addition, the manufacturing method of the surge absorber of the present invention is a non-conductive member, a metal thin film divided by a discharge gap and provided to surround the non-conductive member, and a protective film provided to prevent the transfer to the metal thin film generated during gas discharge In the method of manufacturing a surge absorber having a surge absorbing device having a surge absorbing element, an intermediate film for stress relief is formed in the metal thin film so as to prevent the metal thin film from being deformed by the stress of the protective film, and a metal thin film in the intermediate film After deposition, the protective metal is formed by chemically converting the deposited metal thin film into a conductive ceramic thin film using a reaction gas.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 is a flowchart illustrating a process of manufacturing a surge absorber according to an embodiment of the present invention. Referring to FIG. 2 with reference to FIGS. 3 to 6, first, as shown in FIG. 3, the metal thin film 11 is placed on a non-conductive member 10 made of a cylindrical alumina (Al ₂ O ₃ ) rod or the like. Deposit. In this case, the metal thin film 11 is made of titanium (Ti), and the titanium (Ti) is deposited to surround the non-conductive member 10 by a sputtering method. The sputtering method involves placing a solid material to be deposited on the surface of an object in a vacuum chamber and then exciting atoms or molecules from the surface of the solid material by bombarding energetic particles on the surface of the solid material using a plasma generated during high voltage discharge. It is a method of depositing a solid material on an object. When depositing the metal thin film 11 by the sputtering method, argon (Ar), which is an inert gas, is used as a plasma forming gas, and when the deposition rate is 30-40 sccm, the deposition rate is about 30 nm / min.

When the thickness d of the metal thin film 11 deposited on the non-conductive member 10 reaches a preset thickness, the metal thin film is further supplied by supplying a reactive gas for forming a protective film into the vacuum chamber as shown in FIG. 4 in step 101. On 11, a protective film is formed by the conductive ceramic thin films 11a and 11a. For example, when the metal thin film 11 is made of titanium (Ti), and the titanium nitride (TiN) is formed from the conductive ceramic thin film 11a, when the thickness of the titanium thin film is about 2 μm, the inside of the vacuum chamber Nitrogen gas (N ₂ ) is further supplied. At this time, the deposition ratio is adjusted by adjusting the mixing ratio of nitrogen (N ₂ ) and argon (Ar) to 5: 5. The outermost surface layer of the titanium thin film is chemically changed to titanium nitride (TiN) to form a protective film by additionally supplied nitrogen gas (N ₂ ), wherein the conductive ceramic thin film 11a serving as the protective film is a metal thin film ( 11) is formed in a shape surrounding the entire surface.

At this time, the thickness ratio of the metal thin film 11 and the conductive ceramic thin film 11a is very important in relation to the response speed of the metal thin film 11. For example, if the thickness of the titanium nitride (TiN) acting as a protective film is too thin, the protective effect of the titanium (Ti) thin film is reduced, on the contrary, if the thickness of the titanium nitride (TiN) is too thick, the electrical resistance is titanium nitride (TiN). Since it is about 100 times higher than titanium (Ti), the series resistance of the surge absorber increases due to an increase in the electrical resistance of the entire thin film, thereby causing a problem in that the response speed to overvoltage is reduced. Therefore, in the present invention, the thickness d2 of the conductive ceramic thin film 11a is determined to be within 1/2 to 1/10 of the thickness d1 of the metal thin film 11. For example, the thickness of titanium (Ti) is 1. When the thickness is µm, the thickness of titanium nitride (TiN) is maintained at 0.1 µm.

After forming a protective film made of the conductive ceramic thin film 11a on the metal thin film 11, as shown in FIG. 5, the metal thin film 11 is laser-cut in order to allow the metal thin film 11 to act as a discharge electrode. As a result, a discharge gap 12 having a predetermined length for dividing the metal thin film 11 is formed. At this time, the protective film is divided together with the metal thin film 11 by laser cutting, and the metal thin film 11 has a shape in which two divided surfaces face each other in the longitudinal direction.

3, 4, and 5 through the manufacturing process sequentially to manufacture a surge absorption element.

After the surge absorbing device is manufactured, as shown in FIG. 6 in step 103, first, the terminal electrodes 22 are electrically connected to both ends of the surge absorbing device so as to electrically connect the surge absorbing device to the outside. At this time, since the metal thin film 11 is covered and protected by the conductive ceramic thin film 11a, the terminal electrode 22 is connected to the conductive ceramic thin film 11a electrically connected to the metal thin film 11. Then, the terminal electrode 22 is electrically connected to the sealing electrode 21 to which the lead wire 23 is electrically connected, and then filled with an inert gas 20a such as argon (Ar) in the accommodation tube 20. Complete the manufacture of the surge absorber by maintaining the insulation.

Therefore, when an abnormal voltage occurs, the overcurrent caused by the abnormal voltage reaches the metal thin film 11 along the lead wire 23 via the sealing electrode 21, the terminal electrode 22, and the conductive ceramic thin film 11a. Gas discharge occurs in the discharge gap 12 by the surge energy according to the overcurrent. Surge energy is dissipated by gas discharge and is converted into discharge energy such as light or electric shock waves while reacting with the inert gas 20a. In this case, the discharge energy is not directly transmitted to the metal thin film 11 by the conductive ceramic thin film 11a surrounding the metal thin film 11, but is applied to the conductive ceramic thin film 11a. As described above, this conductive ceramic has better surge resistance and heat resistance than the metal thin film 11, so it can endure discharge energy, effectively preventing the metal thin film 11 from being damaged by the discharge energy.

Hereinafter, in a single thin film structure in which titanium (Ti) is used as the metal thin film and titanium nitride (TiN) is formed as the conductive ceramic thin film, and only the metal thin film or the conductive ceramic thin film is deposited without using a protective film. Experimental results of measuring the change of discharge start voltage and change of response speed of surge absorber will be explained.

Titanium nitride (TiN) and titanium (Ti) thin films were deposited on cylindrical alumina (Al ₂ O ₃ ) rods under the same conditions. In addition, an argon gas was used as an inert gas filled in the accommodation tube.

The following is a description of the table showing each test condition and result.

Table 1 shows the rate and response rate of discharge start voltage after applying Telecom Wave (10 / 700Hz) and 1.5kV (37.5A) surges (30 seconds, 5 times).

TABLE 1

Type of film Discharge start voltage before surge (V) Discharge start voltage after surge % Change Response speed Ti / TiN (1) 300 310 3.33 1.8㎲ Ti / TiN (2) 310 330 6.45 TiN (1) 310 310 0.00 2.4 ㎲ TiN (2) 310 320 3.23 Ti (1) 290 360 24.14 1.6 ㎲ Ti (2) 320 360 12.5

Table 2 shows the rate and response rate of discharge start voltage after applying the combination wave (1.2 / 50 Hz) and 1.5kV (750A) surges (20 seconds, 5 times).

TABLE 2

Type of film Discharge start voltage before surge (V) Discharge start voltage after surge % Change Response speed Ti / TiN (1) 290 320 10.34 200㎱ Ti / TiN (2) 290 300 3.45 TiN (1) 310 320 3.23 280 yen TiN (2) 320 370 -10.00 Ti (1) 280 600 114.29 300 yen Ti (2) 300 1,550 416.29

Table 3 shows the rate and response rate of discharge start voltage after applying the combination wave (1.2 / 50 ㎲) and 2kV (1,000A) surge (20 seconds, 5 times).

TABLE 3

Type of film Discharge start voltage before surge (V) Discharge start voltage after surge % Change Response speed Ti / TiN (1) 270 700 159.26 200㎱ Ti / TiN (2) 280 820 192.86 TiN (1) 310 1,100 254.84 240㎱ TiN (2) 310 470 51.61 Ti (1) 310 1,480 377.42 720㎱ Ti (2) 310 1,510 387.10

Table 4 shows the rate and response rate of discharge start voltage after applying the combination wave (1.2 / 50 /) and 3kV (1,500A) surge (every 20 seconds, 5 times).

TABLE 4

Type of film Discharge start voltage before surge (V) Discharge start voltage after surge % Change Response speed Ti / TiN (1) 290 1,000 244.98 200㎱ Ti / TiN (2) 290 1,000 244.98 TiN (1) 310 1,080 248.39 400 yen TiN (2) 310 1,550 400.00 Ti (1) 310 2,120 583.87 1,240 yen Ti (2) 310 1,910 516.13

Table 5 shows the discharge start voltage change rate and response speed after applying the combination wave (1.2 / 50 ㎲) and 4kV (2,000A) surges (20 seconds, 5 times).

TABLE 5

Type of film Discharge start voltage before surge (V) Discharge start voltage after surge % Change Response speed Ti / TiN (1) 310 900 233.33 180㎱ Ti / TiN (2) 130 920 240.74 TiN (1) 310 damage - 260 yen TiN (2) 310 damage - Ti (1) 320 damage - 168 yen Ti (2) 330 damage -

As a result of the test, when the titanium (Ti) thin film is used alone, it can be seen that not only the voltage change rate is large but also the response speed is increased due to the film breakage.

However, the surge absorber 10 having a double thin film structure using titanium (Ti) / titanium nitride (TiN) thin film under all conditions has excellent heat resistance and resistance as in the case of a single thin film structure using titanium nitride (TiN) alone. While showing surge characteristics, it shows faster response speed than surge absorber 10 having a single thin film structure using only titanium nitride (TiN) alone.

In addition, as shown in Table 5, all surge absorbers 10 are damaged when the most severe conditions of Combination Wave (1.2 / 50 Hz) and 4 kV (2,000 A) surges (20 seconds interval, 5 times) are applied. In the case of the thin film structure, the lower ductile titanium (Ti) prevented the breakage of the titanium nitride (TiN) of the upper brittleness.

On the other hand, when the thickness of the conductive ceramic thin film is greater than a predetermined ratio relative to the thickness of the metal thin film, a relatively rigid conductive ceramic thin film may cause stress to deform the flexible metal thin film.

Hereinafter, a process of further depositing an intermediate film for stress relief between the metal thin film and the conductive ceramic thin film will be described.

7 is a flowchart illustrating a process of manufacturing a surge absorber according to another embodiment of the present invention. Referring to FIGS. 8 to 13, the metal thin film 31 is deposited on the nonconductive member 30 by the sputtering method described above with reference to FIG. 3. At this time, the thickness d 'of the metal thin film 31 in FIG. 8 is larger than the thickness d of the metal thin film in FIG.

When the thickness d 'of the metal thin film deposited on the non-conductive member 30 reaches a predetermined thickness, as shown in FIG. (31a) is formed. For example, when the metal thin film is made of titanium (Ti), nitrogen gas (N ₂ ) is additionally supplied into the vacuum chamber. At this time, the deposition ratio is controlled by adjusting the mixing ratio of argon (Ar) and nitrogen (N ₂ ) to 5: 1. Part of the surface of the titanium thin film is chemically changed to titanium nitride (TiN) by the additionally supplied nitrogen gas (N ₂ ) to form an intermediate film in which titanium (Ti) and titanium nitride (TiN) are mixed. In this case, the intermediate layer 31a is conductive and is formed in a form that surrounds the entire surface of the metal thin film 31. In addition, the density and thickness d3 'of the intermediate film 31a are less than the density and thickness of the conductive ceramic thin film described later deposited on the intermediate film 31a, and the density and thickness d1' of the lower metal thin film 31. The thickness of the metal thin film 31 is prevented from being deformed by the stress caused by the conductive ceramic thin film. At this time, the density and thickness control of the intermediate film 31a is determined by adjusting the ratio of nitrogen (N ₂ ) and controlling the chemical reaction time.

In this case, the response speed decreases because the total series resistance of the surge absorber is determined by the thickness ratio of the metal thin film (d1 '), the thickness of the intermediate film (d3'), and the thickness of the conductive ceramic thin film. The thickness d3 'of the interlayer film is set to a minimum thickness capable of relieving the stress of the conductive ceramic thin film.

In operation 112, the metal thin film 40 is first deposited by a sputtering method to form the conductive ceramic thin film 40 as a protective film on the intermediate film 31 a as shown in FIG. 10.

Thereafter, as shown in FIG. 11, in step 113, a reactive gas is further supplied to the vacuum chamber to chemically change the metal thin film 40 deposited on the intermediate film 31a to the conductive ceramic thin film 40 'to form a protective film. The metal thin film 40 is chemically changed to the conductive ceramic thin film 40 '.

Thereafter, as shown in FIG. 12, in step 114, a discharge gap having a predetermined length for dividing the metal thin film 31 by laser cutting the center of the metal thin film 31 so that the metal thin film 31 can act as a discharge electrode. To form. In this case, the metal thin film 31, the intermediate film 31a, and the conductive ceramic thin film 40 'are divided together by laser cutting, and the metal thin film 31 has two divided surfaces facing each other in the longitudinal direction. .

8, 9, 10, 11, and 12 through the manufacturing process in order to complete the manufacture of the surge absorbing element and then in step 115 as shown in Figure 13, after the electrical connection of the terminal electrode 22 to the surge absorbing element The terminal electrode 22 is electrically connected to the sealing electrode 21 to which the lead wires 23 are electrically connected, and an inert gas 20a such as argon (Ar) is filled in the accommodating pipe 20, and insulation is provided. To complete the manufacture of the surge absorber. At this time, since the metal thin film 31 is covered and protected by the intermediate film 31a and the conductive ceramic thin film 40 ', the terminal electrode is connected to the conductive ceramic thin film 40' which is finally connected to the metal thin film 31.

Therefore, even if the stress of the conductive ceramic thin film 40 'is generated, the intermediate film 31a absorbs and dissipates the stress, so that the effect of the stress is not transmitted to the metal thin film 31, so that the metal thin film 31 may be deformed. none.

In addition, since the interlayer 31a is relatively softer than the conductive ceramic thin film 40 ', the conductive ceramic thin film 40' may be discharged even when the discharge energy generated during gas discharge slightly exceeds an acceptable level of the conductive ceramic thin film 40 '. ) Can be broken to some level. As a result, an additional effect of relatively increasing the surge resistance and heat resistance of the conductive ceramic thin film 40 ′ by the interlayer 31a is obtained.

On the other hand, the embodiment of the present invention has been described for forming the protective film over the entire surface of the metal thin film, but is not limited to this, the acceptance of the metal thin film which is the actual damage of the metal thin film by the discharge energy generated during gas discharge The protective film can also be formed only on the surface exposed to the inert gas in the tube.

As described in detail above, the present invention improves the response speed to the abnormal voltage by using the metal thin film as the discharge electrode, while absorbing the abnormal voltage within a short time, while forming a protective film on the metal thin film by the discharge energy By preventing damage, there is an effect of extending the service life of the surge absorber repeatedly.

In addition, the present invention has the effect that it is possible to simplify the manufacturing process of the surge absorber according to the protective film arrangement while effectively preventing the damage to the metal thin film by disposing the protective film properly on the metal thin film.

In addition, the present invention forms a conductive ceramic thin film as a protective film on the metal thin film, so that the flexible metal thin film can be made even under the most severe conditions such as the combination wave (1.2 / 50 Hz) and 4 kV (2,000 A) surge (20 seconds interval, 5 times). Since the shock applied to the conductive ceramic thin film is absorbed to some extent, the surge resistance and heat resistance characteristics can be improved even if the thickness of the conductive ceramic thin film is not too thick, so that the response speed is not significantly reduced even by the conductive ceramic thin film It has an effect.

In addition, when the thin film is formed by sputtering, the conductive ceramic thin film can be formed only by changing the reactor body without replacing the target or opening / closing the vacuum chamber, thereby preventing a decrease in productivity.

Claims (8)

A method for manufacturing a surge absorber comprising a surge absorbing element housed in a receiving tube filled with an inert gas and having a nonconductive member and a discharge electrode provided in the nonconductive member and divided by a discharge gap, Depositing a metal thin film on the non-conductive member, A protective film is formed on the metal thin film to prevent the discharge energy generated when the gas discharges due to the abnormal voltage to the metal thin film. And forming a discharge gap so as to divide the metal thin film so that the metal thin film can act as a discharge electrode. The method of claim 1, wherein a protective film is formed by chemically changing the surface of the metal thin film using a reaction gas. The method of claim 2, wherein the protective film is a conductive ceramic thin film. 4. The method of claim 3, wherein the conductive ceramic thin film is electrically connected to a sealing electrode provided for sealing the receiving tube and electrical connection with the outside. The method of claim 1, wherein a surface of the metal thin film is formed of a titanium nitride (TiN) protective film using nitrogen gas in the metal thin film made of titanium (Ti). The method of claim 1, wherein the thickness of the protective film is formed within 1/2 to 1/10 of the thickness of the metal thin film. A surge absorber having a nonconductive member, a metal thin film divided by a discharge gap and provided to surround the nonconductive member, and a surge absorbing element having a protective film provided to prevent the metal thin film from being generated during gas discharge. In the manufacturing method, Forming an interlayer film for stress relief in the metal thin film to prevent the metal thin film from being deformed by the stress of the protective film, And depositing a metal thin film on the intermediate film and chemically converting the deposited metal thin film into a conductive ceramic thin film using a reaction gas to form the protective film. The method of claim 7, wherein the intermediate layer is formed to have a density greater than that of the metal thin film and less than that of the conductive ceramic thin film.

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